Method of applying steel reinforcement to existing columns



Hg. 30, 1949. J. D. BOLTON 2,480,180

METHOD OF APPLYING STEEL REINFORCEMENT TO EXISTING COLUMNS Filed June 5,1948 2 Sheets-Sheet l INVENTOR.

J. D. BOLTON METHOD OF APPLYING STEEL REINFORCEMENT TO EXISTING COLUMNS2 Sheets-Sheet 2 Aug. 30, I949.

Flled June 5 1948 Fatented Aug. 30,1949

METHOD OF APPLYING STEEL REINFORCE- MENT TO EXISTING COLUMNS John D.Bolton, Evanston, Ill., assignor to John D. Bolton & 00., Inc.,Evanston, 111., a corporation of Illinois Application June 5, 1948,Serial No. 31,373

This invention has to do with the strengthening of structural columns inexisting buildings, as distinguished from new building construction, andit deals specifically with the problem of applying helical steel-rodreinforcement to existing columns, in situ, as a step preliminary to theapplication of added external thicknesses of concrete.

A highly favored form of concrete column reinforcement consists of acontinuous steel rod helix expanded lengthwise of the column, togetherwith a group of vertical reinforcing rods tied to the helix and equallyspaced circumferentially of the column; and on new building constructionthe helices can be coiled in advance to the desired radius of curvatureand put in place in the forms without any particular difficulty. Butsometimes it is necessary to reinforce existing columns by addingthereto further thicknesses of concrete; and Where, in such cases, thearchitect or engineer specifies helical reinforcement, the problem ofapplying the reinforcement to the existing columns has proved to be aformidable one, because it is not practicable to coil the steel rodbefore setting it in place, as is done on new work.

As an example, take a job involving a large factory building wherein thefloor space is occupied by machinery and other fixed equipment, andwhere it is necessary to proceed without removing any of the machines orequipment or interfering materially with normal factory operation-itwould not be possible to apply the helical reinforcement to the existingcolumns by any of the methods or procedures heretofore known. To meetsuch a situation, according to the present invention a portable rodbending machine is provided to be moved from column to column and set inplace immediately adjacent each successive column, and then, with themachine so positioned, the rod is run through the machine and theresultantly curved rod is led around the column as it emerges from themachine. By so doing it is possible to bend and apply to each column aspecified length of perhaps six hundred lineal feet of round steel rodat the rate of about five minutes per column-a most satisfactorysolution of the problem above stated, and one which may be achievedwithout significant interference with normal factory operations.

Portable rod-bending machines have previously been known, and no claimherein is made to any novelty of major importance in the disclosedbending machine per se. But the method herein 4 Claims. (01. 29-155) tobe described, which comprises bending a long rod into a helix of manyturns and simultaneously wrapping the same around an existing column, asit emerges from the bending machine, is a feature of primary importancewhich, in short, is the substance and purport of the instant invention.

Referring now to the accompanying drawings,

Figure l is a small scale elevational view of an existing buildingcolumn, together with upper and lower floor sections, showing asteel-rod helix which has been Wrapped around the column and expandedaxially, the vertical reinforcing rods and new concrete having beenomitted from this view in order to simplify the showing;

Fig. 2 is a perspective view showing the lower end portion of anexisting building column, together with a portable bending machineresting on the floor adjacent the column, and illustrating how thereinforcing rod is bent and passed around the column as it emerges fromthe machine;

Fig. 3 is a horizontal View in section, taken on line 3--3 of Fig. 2;

Fig. 4 is a vertical sectional view, taken on line 44 of Fig. 3;

Fig. 5 is a sectional view, taken on line 5-5 of Fig. 3; and

Fig. 6 is a fragmentary section, taken on line 6--6 of Fig. 3.

In Fig. 1 there are shown two successive floor sections to and I2, andan intervening column M, which is to be reinforced, and around whichthere is shown wrapped a helix 15 consisting of a considerable number ofturns of steel rod. And in addition to the helix I5 the reinforcementordinarily would include a number of vertical steel rods equally spacedaround the column and secured to the helix by means of wire ties. Thevertical rods have not been shown because they would tend to obscure theshowing of the helix, and the invention is concerned only with the helixand its application to the column;' and for a like reason thesubsequently applied added shell of concrete has been omitted from theview.

It will, of course, be understood that after the reinforcing steel hasbeen put in place, a form is built around the column, enclosing theadded reinfor-cement, and the concrete then poured'in or perhaps appliedby the gunite process. So far as the present invention is concerned itis of no consequence whether the column to be reinforced is made ofconcrete or of wood, steel, brick or any other material; and thecross-section of the existing column, whether round or rectangular, is amatter of indifference.

Unless the helix i5 is of very much larger di- 3 ameter than the columnto be reinforced, it would be impracticable, if not utterly impossible,to apply a previously formed helix to the column, assuming the helix tobe made of stiff steel rod, as distinguished from relatively flexiblewire; but the method of procedure according to the present inventioncompletely and successfully circumvents that difficulty.

For the purpose of carrying out my invention, I employ a portablebending machine, such as is shown in Figs. 2-6, inclusive, andidentified as a whole by the reference numeral 20: Thisimachine is welladapted to the job for'"which*'lt"is= intended because thebending-rollscanabe.placed conveniently close to the column.Thesteeltrodt' is bent by such a machine and simultaneously the bentportion of the rod is passed around the.

existing column, as it emerges from the bending rolls as illustrated inFigs. 2 and 3 wherein sforl" the sake of conformity with Fig. 1, I haveidentified the. steel rodby the. reference numeral Hi, this being thesame numeral usedforeidentifying the helix in Fig. 11

EromFig. 3' it willnbetseen that therodllfi; is being passed through thebending machine, wherein it is first straightened. andthenmbent. tothemequired radius of. curvature;. and thatlthe curved rod emergingiromthemachine is directed around the column, thus forming amultiple.turn coil l encircling the-column. As the coil builds up, its weightincreases so that it may be necessary for the workmenin attendance. to.lift and pull it arou-ndwith suitable tackle; .and'it may be helpful toplace some heavy blocks ,on thefloor and against the columnv toaprovidesupports for thecoil .so that itcan be manipulated around :the columnmore easily. In'Fig.v 21 thev coil I5 is shown asif floating in space,but it will be understood that this has-been done to. clarify thedrawing, and that in actuality the coil will .rest.

partlyon the floor and partly on the bending machine unless some othercoil-supporting means isprovided; such as the above-suggested blocks.

The bending machine includesa truck con:- sistlng; of a steel platform2| --equippedrwlth-i-our roller casters 22. Extending horizontally fromthe platform 21 and'spaced-a-part, -(see Fig, 3) are two arms 24, 24which bear against the column and serve to position the machine:relatively to the :column; The machine may beanchored to the column bymeans of a steel-band -2'5,.bhe- -encls of which are detachablyconnected-to the arms2 3 While the band 25-serves-toanchorthe :bendi-ngmachine with certainty, andmay in some-cases be important operationally,itschief value is that ofaa'safetyprovision. If used in :a factory;where there are employees present and movingi about, a fixed anchorageof the machine may become important to prevent injury resultingfromiinadvertent displacement and rollingsof the machine acrossthe.floorr;

Welded to" the platform'21 and rising vertically therefrom are atpairofspacedtchannel irons; 25;; 265011 which is pivotally-mounted :a base:plate: 21 forming a support for an electric ;motor-2E8,- -havingFapulley 29, which is connected through a v-beltz3fl to the pulleyfizl ofa right-angledspeed reducing "transmission 32. A-coil spring 33-iisattached ?at its upper end to? the 'basewplate 25F and at its'flower.end to the-platform 2 I, and serves :to keepthe be1t30 undersuitabletension.

The transmission 32*ismounted on a bracket 34' which, in turn, iswelded-to theplatform .24.; and it includes a vertical shaft whichex-tends downwardly through the-platform 2i and carries 4 a pinion 36(see Fig. 6) the function of which will presently be explained.Rotatably mounted on vertical studs 38 which are secured to the platform2| are six straightening rolls 39, ar-

ranged in pairs, the members of each pair being spaced apart justsufliciently to receive the rod l5; and positioned at the receivingendof the straightening rolls is a guide plate 40, welded to theplatform 2| and having a horizontally elongated opening of a width,vertically, sufficient to clear the rod. The rod is regularly shipped tothe sites-of I'zoperation' in the form of coils, since it is too Icngto'be handled otherwise, and it must besstraightenedabefore being bent tothe desired curvature. That isithe function of the straightening rolls39':

Immediately adjacent the output end of the group of straightening rolls39, there is mounted on'the' platform 2| a pair of grooved driving orfeed rolls 42, 42, each off'which is keyed to a verii-631 5113111143;.43 journaled in' suitable bearings andeachmarryinga gear 44,- 24 at itslower end see-Fig. 6). The two latter gears are inter.- meshediand -ofthe same pitch diameter, ,so that theztwo ieedrollsAZ, 42. are .drivenat the same speed,- andone of :said gears is also meshed witthespinionQBG throughwhich the feed rollsare driven.

Ite'will be. apparent that the. feed rolls. 42, 42 grip thelrod. l5:andserve toforce the same lengthwise-throughthestraightening rolls; Asthe rod emergeswfrom the ieed rollsiitlpasses between-apairofguidarollslfi, which, like the straightening,rolls;.are-mounted-onvertical studs 63,41; and-ilfzisithereupon 'eng-aged'by a bendiugroll 55which cooperates; with the guide rolls 46, 8 to applybending'pressure-to the rod. The hen-sling roll z5llds-rotatablymountedon astud.5! the lower endloiwhich :isssecured'to a carriage 52 whichiis slidably-mounted in a guide member tie and provided with an upstanding lug 54 towhich is pivotally connected by'means of a pin 55; avtwopieceelinkififorming an armxof a toggle 5'"! whose other'a'rmcomprises: a link 58'; The latter is pivotallyconnectedxatnone enditothe adjoining 'endof thelink l'ss bymeansof a pin seam: at'its otherend'iti-is" pivotally' connected by a pin: 68 to'-'a-'-clevis B l-which, inturn, is fixedly secured toone'endof anadjusting screw '62, which passesthrough-an" aperture-in a lug 63 welded to the platform Hi the adjustingscrew being secured by a'paii' of lock nuts 64', 64; An upstanding arm65 is"rigidly"secured to the link 58 and serves as a means'whereby a'workman can manipulate the toggle" 51: to" effect forward and backwardmovement offthe bending roll 50 and its carriage 52;

Thcoperative position of the bending roll 50 is determined by theadjustment of the screw 62 whoseupositionis. then fixed by adjustment ofthe lock. nuts 64.. T'he v curvature imparted to the rodis, .oicourse, aiunction of the operative position ofsthenbending roll, relative to theguide rolled-BI l'nworder to ,startthe bending opera tion wheniafreshrod'is inserted, it is necessary tometract the bending roll 50 andthen force it forwardly against the. rod, andthis is accomplished bymeansof. the toggle arm 65 in the manner already, explained; It isdesirable to ad'- justi-the bendingmachine o thatithe curvatureimpartedto therodwill resultin a helix ofthe prescribed-diameter..Thiscan readily be..done Joy-runningi throughltheimachine a lengthof..;rod and-measuring itscurvaturewitha templet, as

adjustments proceed, until exactly the right curvature is obtained.

I claim:

1. The method of applying an encircling steelrod coil to an existingbuilding column, which comprises progressively bending the steel rod ata fixed point adjacent the column to the desired curvature and passingthe curved rod lengthwise around the column as the bending operationproceeds forming a multiple turn coil around the column in situ.

2. The method of applying an encircling steelrod coil to an existingbuilding column, which comprises placing a bending machine in a fixedposition adjacent the column and passing the steel rod therethrough tobend the same to the desired curvature, and leading the curved steel rodlengthwise around the column as it emerges from the bending machineforming a multiple turn coil around the column in situ.

3. The method of reinforcing an existing structural column whichcomprises progressively bending a steel rod in a fixed position adjacentthe column to form a multiple turn coil thereof, and continuouslyleading the bent rod around the column, lengthwise of the rod, as thebending operation proceeds, so that the coil, upon completion, encirclesthe column, then axially expanding the coil longitudinally of thevertical dimension of the column to form a helix extending lengthwise ofthe column, disposing a plurality of vertical reinforcing rods in spacedrelation around the column and securing the same to the helix to providesupport for the helix, and then applying to the exterior of the column ashell of plastic concrete mixture of a sufiicient thickness to embed therod reinforcement.

4. The method of applying an encircling steelrod coil to an existingbuilding column, which comprises progressively bending the steel rod ata fixed point adjacent the column to the desired curvature and passingthe curved rod lengthwise around the column as the bending operationproceeds forming a multiple turn coil around the column in situ and thenexpanding the multiple turn coil axially longitudinally of the verticaldimension of the column.

JOHN D. BOLTON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

